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Biology Help Desk: Volume 2^3

Samantha Wright (1324923) writes | about 6 months ago

User Journal 19

The drill! You may know it from my last journals. Ask questions and I'll be happy to help. Feel free to answer any questions you have ideas about yourself, too.

The drill! You may know it from my last journals. Ask questions and I'll be happy to help. Feel free to answer any questions you have ideas about yourself, too.

19 comments

Human skin: How is it a barrier? (1)

Futurepower(R) (558542) | about 6 months ago | (#45197241)

How does skin protect against intrusion of chemicals? How can detergent kill bacteria, but not hurt skin cells? One answer, I'm guessing, is that skin cells are serviced from within. Bacteria depend on outside influence for oxygen, water, and food.

Re:Human skin: How is it a barrier? (1)

Samantha Wright (1324923) | about 6 months ago | (#45197507)

The answer is elegantly simple: it dies. We replace every skin cell on average every 48 or so [nih.gov] days, and there are a lot of them. It does help that nutrients from blood are consistently and reliably available, too, as this means it's much easier for skin cells to recover after damage, but honestly it's mostly just shedding. On top of that, many detergents and other cleaners are designed specifically to interfere with features unique to the normal functioning of bacterial cells, so they're just generally much less toxic to us. If you put human skin and a bacterial colony in a strong acid, the result will be the same.

Wow, thanks. (1)

Futurepower(R) (558542) | about 6 months ago | (#45197659)

Wow! Thanks, Samantha. That subject is very interesting to me. I would like to know even more. I will visit the OHSU library and download the paper to which you linked.

What can I do for you? I know an exceptionally nice man who is serious about marriage who is looking for a wife, if you aren't already married. (I'm a full-service friend. -grin-)

Re:Wow, thanks. (1)

Samantha Wright (1324923) | about 6 months ago | (#45198121)

Thanks for the sentiment, but I've already got that sort of thing planned out. Also even if I didn't, I think there'd be a waiting list.

"waiting list"? Actually, no. (1)

Futurepower(R) (558542) | about 6 months ago | (#45199583)

A problem in talking about these things is that the talking challenges everything people think they know.

Yes, he is friendly with a lot of women. However, it is very, very difficult to find a woman who is serious about marriage. Most just don't want to do the work. He and I talk about that a lot. I'm now happily married, but I looked for 42 years in 33 countries before I found her in Brazil. I'm trying to make it easier for him.

If a woman meets an interesting man, the immediate issue is not whether or not she will marry him, of course. The immediate issue is that it can be extremely valuable to meet a like-minded person. What kind of a relationship she could have with that man is determined later.

Maybe this will be surprising, but here are things that seemed reasonable theories about you after reading your answer to my biology question:

1) You are willing to take a position of leadership. It is very, very difficult to find women who will accept being primary leaders. Or men, but a smaller percentage of women.

I've talked with 10 women about that in the last 3 months. One of them has a Flamenco dance group. She and I have spent hours talking. She is certainly strong in some ways, but doesn't feel comfortable changing Flamenco in a way that would improve its acceptance in the United States. That amazes me.

2) You are trusting of other people; you made an open-ended offer to help with questions about biology.

3) You are caring. You are willing to help strangers like me with questions about biology.

4) You are a good writer, and you like to write. Most people aren't and don't.

After writing this, I read some articles on the celestial mechanics web site. Cadre sounds interesting.

I read Graduate School Supplication [slashdot.org]. I agree with the surface implications. I also agree with the deep implications, which indicate that a university may not be a good place to learn.

Re:"waiting list"? Actually, no. (1)

Samantha Wright (1324923) | about 6 months ago | (#45204709)

While I appreciate your candidness and flattery, this is still not an appropriate venue for pursuing or facilitating the pursuit of romantic relationships, and I'm still taken.

Re:"waiting list"? Actually, no. (1)

tibit (1762298) | about 6 months ago | (#45258553)

I'm reading this thread and I'm wondering: is this *really* happening? I'm glad, in a way, for not being a geek female. I'm worried for my daughter, just a bit.

Re:"waiting list"? Actually, no. (1)

Samantha Wright (1324923) | about 6 months ago | (#45260099)

This is probably the fifth or sixth time since I started posting on Slashdot actively two or three years ago. However, it is the first time someone has... solicited on the behalf of another, and the first time the inquirer had the forethought and considerateness to post directly (and insistently) on a very visible and irremovable journal entry rather than a private email or an obscure story comment.

As most of these messages seem to come from older people, I remain optimistic that this kind of thing is continuing to die out and is not yet at some kind of asymptotic background level.

Re:"waiting list"? Actually, no. (1)

tibit (1762298) | about 6 months ago | (#45266043)

Asymptotic background level, if any, has to go to the very bottom of the waiting list, then :) I enjoy your posts, keep it up.

Re:"waiting list"? Actually, no. (1)

robotkid (681905) | about 6 months ago | (#45281867)

I'm reading this thread and I'm wondering: is this *really* happening? I'm glad, in a way, for not being a geek female. I'm worried for my daughter, just a bit.

Agreed and seconded.

I currently work at a university well known for it's engineering programs and I would be *very* scared to send my daughter here. The ~ 15% female population is alternatively fetishized and objectified, but also not expected to succeed in any highly technical endeavors. My daughter is 3 years old, I'm hoping to teach her to code when she's a little older (project Alice or something similar), but only if she also learns some sort of asymmetric self-defense such as Aikido first. . .

Re:"waiting list"? Actually, no. (1)

Samantha Wright (1324923) | about 6 months ago | (#45284777)

It's hard to know if that'll be entirely necessary. I understand as a father you feel a profound need to protect, but it actually is getting better. You might want to consider sending her to another university, however; schools with an overall more balanced program tend to have an easier time drawing women to more polarized fields.

Re:"waiting list"? Actually, no. (1)

robotkid (681905) | about 6 months ago | (#45285561)

Oh, of course! I really enjoyed going to a school that had a much more balanced range of academic programs, and I guarantee all my engineering friends very much appreciated that environment as well, especially being able to meet motivated and smart people with very different and varied interests.

But even then, the number of female Ph.Ds or faculty members in, say, math, physics, or computer science is a tremendous problem, and noone believes for an instant it has anything to do with innate ability, it's clearly external.

In contrast, the local school's startcraft team is top seeded, and there are so few women in this department that I find myself constantly reprimanding grad students who think injecting innuendo into lab presentations is harmless and acceptable academic behavior.

Quick anecdote. My postdoc advisor was trying to decide between two foreign applicants for the Physics Ph.D program here, both top students from their respective schools, and not knowing the overseas academic institutions very well, he asked one of the scientists in our group from the same country to rank the two applicants. He took all of 30 seconds and said "admit the woman". My advisor was shocked it took so little time, he asked why, the credentials seemed equivalent. The scientist replied "she's the only woman in her graduating physics class from a top university, so she had to prove herself ten times harder than any man to end up with the same grades, she's clearly the better scientist though it doesn't show on paper".

It's hard to know if that'll be entirely necessary. I understand as a father you feel a profound need to protect, but it actually is getting better. You might want to consider sending her to another university, however; schools with an overall more balanced program tend to have an easier time drawing women to more polarized fields.

Re:"waiting list"? Actually, no. (1)

Samantha Wright (1324923) | about 6 months ago | (#45288201)

This [genderbiasbingo.com] exceedingly well-informed (and justly so) guy pretty much covers and has experienced everything there is to say. Perhaps the most bizarre thing is how deep the bias about perceived skill runs; Barres argues that seemingly well-adjusted people will unconsciously view a female scientist's work more critically simply based on gender (although his own anecdotal experience is hardly under rigorous control and it's possible he really did get better.)

On the other hand, when I got to graduate school and was going through potential PIs, I commented to one of them (the only woman in the bunch and one of the few in the department) that the gender balance was much weaker than it had been at my alma mater—there, both the students and the faculty were within 20% of parity, despite both departments being CS. Her view was one of internalized pressure, that a lack of suitable role models in prestigious institutions directly causes assumptions about one's own abilities, so women don't generally push to try and get into better programs.

Looking back, I can't exactly say I disagree with her assessment. If I'd had any friends at all in undergrad and hadn't been quite as ignorant about the gender disparity when I toured the campus the first time around, I might've stayed in my home town. (No doubt to the polite chagrin of my parents.) As it turned out, though, I ended up in a cross-departmental posting, and my lab is actually mostly female—or was, anyway, until last month, when the newest students started. Now it's 50/50, I guess, not counting the male PI and a perennial undergrad or two.

Re:"waiting list"? Actually, no. (1)

robotkid (681905) | about 6 months ago | (#45288355)

There was a study in PNAS within the last year that was eye-opening, especially in that female faculty were just as biased against a fictional resume for a lab manager (read gap year student technician) if the name was feminine rather than masculine.

http://www.pnas.org/content/109/41/16474.full [pnas.org]

Of all the numerous commentaries on why this might be so, I think the above-average but not stellar academic credentials (B+ student) is what did it. For a normal
(read male) evaluation, the narrative might be "this guy just needs some good mentoring while he figures out what to do next", whereas for a female name, it might be "she's OK but she's not stellar, and she needs to be stellar to succeed in this male dominated field, so let's not mislead her".

Re:"waiting list"? Actually, no. (1)

Samantha Wright (1324923) | about 6 months ago | (#45288465)

Increasingly female faculty are reading studies like this and taking corrective action, but you can imagine there's still lots of room for improvement. As Barres articulates, the meme responsible for the overall disparity is that men have a broader variation than women in intelligence (which, sadly, I myself have believed in the past), but this goes back to some very flawed and old IQ test results that, unsurprisingly, can be influenced by your level of self-confidence! If you go through his slides (and I really recommend you do), you'll see that there are some pretty big names that defend the notion as it stands even though they should know better than to trust the source.

Psychology question (1)

neonKow (1239288) | about 6 months ago | (#45279579)

I am not sure if this is completely on-topic, but how did humans evolve such complex, and often disfunctional, psychologies/behaviors/I'm not sure what to call them?

I can understand if an eating disorder developed as a side-effect of beneficial adaptations, but I've read that somewhere around 1 in 6 people have suffered from depression. How did this happen, and how did humans make it this far despite what seem like fairly debilitating mental issues affecting so many of us, from eating disorders and depression to schizophrenia and borderline personality disorder?

And where on earth did stockholm syndrome come from?

Re:Psychology question (1)

Samantha Wright (1324923) | about 6 months ago | (#45285505)

I'm not a psychologist (and Slashdot just ate half my post), but I might be able to satisfy your curiosity on this matter.

Evolutionary psychology is an ideology that holds that most human quirks were, at some point, useful. Usually this involves some romanticized neolithic society, and it's been shown many times that it's probably mostly garbage and definitely depends on circular reasoning in some cases, but there are some things that can be somewhat explained by it. Depression seems to be one of them.

Another key evolutionary consideration, which is not part of evolutionary psychology, is that modern, Western society lowers the bar a great deal. Life puts expectations on us that are quite different from the expectations it put on our ancestors, and that means that some traits may be more excusable, or even desirable, when they were previously a problem.

Depression rates are not uniform [cdc.gov]. Depression is triggered by experiences, so if you live under good conditions or are preoccupied with survival, then it's probably not a concern at all. Check out this global map [wikipedia.org]—it's too complex to explain in just a few sentences, but you get the impression that there's circumstantial meaning behind it. There are genetic considerations, of course [slashdot.org], but they mostly just seem to promote pessimistic behaviour. (Two more notes: Europeans have a much higher rate of having the particular gene variant from that last link. Unrelatedly, both France and Louisiana show up as having very high depression rates on those two maps. Might be something heritable going on there.) It seems easy to suggest that this kind of pessimism might actually be useful, in that it makes us more critical and cautious if it doesn't break our backs.

Schizophrenia is another Western civilization linked illness [wikipedia.org] (annoyingly, this graph is coloured backward from the other Wikipedia one.) Evolutionary psychology falls down in this case; a schizophrenic may occasionally make a convincingly weird prophet, but it generally seems to be a bad thing. At the same time, researchers think that schizophrenia, like autism, is affected much more by chemicals in the environment. Perhaps more plausible is the second line of reasoning, that it comes linked with the demands of a more analytical mind. Certainly John Nash [wikipedia.org] would say so. As people gain the freedom to marry who they please, the likelihood of two similar people accidentally causing the genetic equivalent of inbreeding increases.

Eating disorders are a whole other planet. The modern anorexia rate is a result of pop culture; it literally didn't exist a century ago. Compulsive overeating is seen in many animals, on the other hand, and seems to just be an unexpected scenario—if food is available, we eat it. Eating yourself to death is pretty hard when you have to burn a thousand calories to hunt a deer or gather berries. We rely on self control and other social constructs to stop these things. (And four hundred years ago, being overweight was considered a sign of wealth, and was hence attractive in Europe.) Don't mistake obesity for overeating, though—it's well-established at this point that many obese people actually have [kenyon.edu] an obscure immune disorder that causes an intestinal infection, which then causes weight gain. It's purely bad luck, but probably caused by bad factory farming practices.

BPD, as a mixture of neurosis and psychosis, rather simply comes from absolute and extreme demands mixed with an analytical predisposition. It's a little less common (2-6% of Americans), but it's pretty straightforward to understand how the same experiences that give rise to depression can cause it.

Stockholm syndrome serves a rather clear-cut evo-psych purpose—if you don't learn to befriend your captors, you've got a much higher chance of being killed by them. Assuming the captors are a tribe you've just been assimilated into, this suddenly becomes pretty critical. Also keep in mind that Stockholm syndrome is the deep end of the pool; if you scale the mechanism back to less hostile situations, it's essentially the same thing that happens when you try to make peace with someone who hates you.

Re:Psychology question (1)

neonKow (1239288) | about 6 months ago | (#45289847)

Thanks for the super in-depth reply. As always, your responses are always really interesting. How did you get the idea to start this Q&A thing anyway?

I never knew how country-specific a lot of these disorders were. I think I follow how depression and BPD could arise and how Stockholm syndrome could help. I don't really understand how schizophrenia could be linked to more analytical minds, but I guess our brains and bodies ARE a bunch of spagetti code, so I'll have to look into that.

I also see how obesity and other unhealthy eating habits can be a result of our easy access to food and lack of exercise, although that doesn't cover all of over-eating. I've been told that our brains react similarly when we are given food to when we are given love, and I guess that fits in well with a theory of how food helps us with bonding with friendly people.

However, (follow-up question!) even if anorexia and/or bulimia nervosa are effects of modern culture, aren't the cultural pressures that cause people to turn toward starving themselves the same as the ones that caused people to crush their organs with corsets? Wouldn't the urge to conform to what is considered attractive at any period in time be overwhelming enough that someone might be compelled to take it to unhealthy (and possibly detrimental to finding a mate or raising a child) levels?

Re:Psychology question (1)

Samantha Wright (1324923) | about 6 months ago | (#45297427)

You're welcome! I started doing Q&As after I kept getting random off-topic bio questions on news stories. They've dried up a little, but clearly people are still checking for these journal entries, despite not asking for them, since you and several other people found this one.

Stockholm syndrome is actually a coping mechanism that prevents depression. If you love your captor, that distracts you from the fact that you're imprisoned and being abused. BPD tends to manifest following a lot of deep shatterings of trust (at least, in my experience with some friends who've had it), so it's more likely to manifest after (or perhaps as) the illusion of love falters or is proven less than perfect.

A few months ago I wrote a short article [celestialmechanics.net] talking about some computer-like aspects of how the brain works. One of the features in particular that I examined was dreaming behaviour—how sleep gives the brain time to refresh itself and clean up artefacts and imperfections in how it works and what it knows. One of the dangers of not getting proper sleep is overfitting—the expectation that everything must fit an exact category, value, or relationship; this is the same as neurosis when it happens in our reasoning skills. In other parts of the brain, though, overfitting can cause hallucinations and inconsistent logic as the brain tries to fill in gaps that it can't handle, features that are a hallmark of both schizophrenia and extreme sleep deprivation. If you've ever seen the film A Beautiful Mind, it's pretty easy to appreciate how tightly linked Nash's genius was to his propensity for paranoid delusions.

The food–love association does play a role in depression- and anxiety-triggered overeating. In particular, chocolate, much moreso for women than men, has a pretty profound effect on oxytocin (not to be confused with oxycontin!) levels, a hormone that enhances feelings of love and connectedness. (If you can't sympathize with this from personal experience, I'm told that lavender has a similar effect.)

As for body image: many corset wearers would go so far as to have their lower ribs removed in order to achieve a better hourglass figure. And given that wearing a corset for a long period of time dramatically increased chances for complications during pregnancy, I think I'd say it was pretty messed up. (Although sadly the maternal mortality rate during delivery was quite awful for most of Western civilization's history.)

However, the media was much less effective at conveying ideals of beauty in the past—due to an line in the Old Testament, cosmetics were widely regarded by most people as being only for prostitutes—and so the average person wouldn't have been aware of such pressures until well into the 20th century when film stars began to set the standards for beauty. That being said, the name anorexia nervosa dates back to the 19th century, and there have been cases throughout history. See Wikipedia [wikipedia.org].

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